What is a permanent foundation for a modular home?

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A permanent foundation is a sturdy, long-lasting base to which the modular home is attached permanently. The volume of a modular home is built in a factory-like environment, though to complete its construction, a modular home has to be attached to a set of foundations constructed right on-site following traditional construction methods. Modular home foundations aren’t unique to this construction method, they are just the same applied in traditionally built houses – but here are the types. 

  • Concrete slab foundation
  • Basement foundation
  • Crawlspace or pier and beam foundation
  • Pile foundation
  • Elevated pile foundation or house on stilts

Modular homes are designed with a clear understanding of where they are being placed. Despite having to be transported from the manufacturing plant to the building site, these constructions will remain permanently in that same location. Therefore, the foundations required to support modular homes have to be highly durable. 

Types of permanent foundations for modular homes

Concrete slab foundation

The most common type of modular home foundation is a block of poured concrete that is laid horizontally on the ground. This is a type of shallow foundation that requires little preparation work and it is often built in a fast and easy way. Consisting of barely a 4 to 6 inches (10 to 15 cm) thick [1]  block of reinforced concrete, a concrete slab is the most affordable type of foundation, hence its popularity.

Basement foundation

Also, a very common choice of modular home foundation, basements represent a cost-effective solution to add some extra space to the modular home. Building a basement requires excavation works since they are built underground usually with materials such as reinforced concrete to grant stability to the modular home.

Crawlspace or pier and beam foundation

Crawlspaces aren’t as popular nowadays, though they are still a good quality solution for a modular home foundation, especially in areas where the ground is commonly wet. [2]. This foundation elevates the modular home about 18 inches (46 cm) [3] off the ground providing natural ventilation between the house and the ground. 

Pile foundation

Pile foundations are a type of permanent foundation that is only used when the soil conditions of the plot of land where the modular home is being built require it. The main purpose of a  foundation is to offer a solid base to the house and when the land is weak on the surface, it is required to dig deep into the ground to find the solid ground the foundation can rest on. Pile foundations consist of very long cylinders sunk as deep as necessary to do so. [4].

Elevated pile foundation or house on stilts

This type of modular home foundation is also unique to a very specific situation. An elevated pile foundation is the ideal permanent foundation solution for modular homes based in areas where floods and/or hurricanes are common. The stilts raise the house off the ground as much as one whole floor to allow the water to run freely without damaging the house. 

References:

  1. Vanderwerf, P. (2007, July 23) Concrete floor slabs Concrete Construction https://www.concreteconstruction.net/how-to/construction/concrete-floor-slabs_o
  2. Patil, R. Pier and Beam Foundation Constructionor https://constructionor.com/pier-and-beam-foundation/
  3. Crawl Space – Everything you need to know about Crawl Spaces Groundworks https://www.groundworks.com/glossary/crawl-space/
  4. What is Pile Foundation? Types of pile foundation Civil Engineering https://civiltoday.com/geotechnical-engineering/foundation-engineering/deep-foundation/176-pile-foundation-definition-types